A man accused of holding a hostage at knife point at a government office in Casper in 2016 recently threatened to kill a federal judge, according to a criminal complaint filed in U.S. District Court on Wednesday.

David Michael Chavis, 36, sent a letter to U.S. District Court Scott Skavdahl at the federal courthouse, 111 S. Wolcott St., postmarked Dec. 27, according to the complaint written by a U.S. Marshal.

Chavis is being held at the Natrona County Detention Center, Sheriff's Sgt. Aaron Shatto confirmed Thursday.

He was declared incompetent to stand trial on charges of kidnapping, aggravated assault and possession of a deadly weapon with intent to threaten the life of another. Conviction on all counts could send him to prison for 20 years to life.

Skavdahl forwarded the letter to the U.S. Marshal: "Specifically, the letter stated Chavis '...will have no choice but to "federally reoffend" and I, will kill you or blow up Casper's federal courthouse" I do know how, and I do have the resources/means. I make no empty threats see my actions as of Aug, 05, 2017 8AM -- 11:45 AM.'"

The criminal complaint did not explain what Chavis meant by his actions on Aug. 5, 2017.

On Monday, Lt. Gordon Clapp of the Natrona County Sheriff's Office contacted the U.S. Marshal about a letter dated Feb. 9 addressed to five people including Skavdahl: "Chavis specifically writes 'I needed to keep myself still attempting to get to trial (one way or another) otherwise, I am at a literal and a virtual impass. And I know of only one last thing which might work and this is to kill a federal employee they will take me to trial for a crime like that, 'SMI or not"".", according to the criminal complaint.

The criminal complaint did not explain what "SMI" means.

Other recipients of this letter were a public defender, a Natrona County District Court judge, and two people related to the Wyoming State Hospital in Evanston.

Both letters were signed by Davis and had a return address of Davis with the address of the Hall of Justice, 201 N. David St., with an apparent reference to the Natrona County Detention Center.

Under federal law, conviction of mailing threatening communications is punishable by up to 10 years of imprisonment.

The case with Chavis began on Aug. 5, 2016, when he entered the office of the Attorney General's Medical Review Panel, 800 Werner Court, and allegedly took a 51-year-old man hostage with a box-cutter.

The building was evacuated, and the Natrona County Special Response Team, along with the Hostage Negotiation Team, handled the incident.

Chavis was arrested shortly before 12 p.m., and the victim was released unharmed.

This marks Chavis' third mental evaluation, requested by Natrona County District Attorney Mike Blonigen, who represented the state in court Thursday morning.

In August, 2017, Natrona County District Court Judge Daniel Forgey declared Chavis incompetent to stand trial. Forgey ordered him to spend about two months at the Wyoming State Hospital in Evanston while doctors determine whether he could again be deemed fit to proceed.